Blender 1.80 doesn't have armatures as we know and love them today, but there are still ways to achieve both IK and FK to some degree...
rigged up one leg of the character just to test if this was viable at all, and it's ... acceptable!!
The OOPS schematic view becomes a sort of rig bone selector in this case, which makes selecting the right "bone" pretty easy actually.
The hard part is finding the right place to put the empties that are part of the skeleton, and determining their radius. I found one solution; adding spheres and then putting empties in the same location, and writing down the scale of the spheres to use as radius
